Bock GEA HGX56e/1155-4 S Semi-Hermetic Compressor

BOCK GEA HGX56e/1155-4 S Semi-Hermetic Reciprocating Compressor

The BOCK GEA HGX56e/1155-4 S is a 6-cylinder semi-hermetic reciprocating compressor engineered for commercial refrigeration, process chilling, and demanding marine HVAC/cargo freezing plants. Equipped with an optimized “e-series” valve plate system, internal force-feed lubrication with a reversible oil pump, and an integrated suction-gas-cooled motor, the HGX56e/1155-4 S delivers exceptional thermodynamic efficiency across high, medium, and low-temperature evaporation envelopes.

The “S” motor variant denotes the reinforced, high-torque motor configuration designed to operate stably under elevated condensing temperatures and broad suction envelopes without tripping thermal cutouts. This unit handles traditional HFCs (R404A, R507, R134a, R407C) and modern low-GWP HFO blends (R448A, R449A, R513A, R450A).

Technical Details:

Key Features

1. High-Efficiency “e-Series” Cylinder Head & Valve Design: Streamlined suction and discharge gas channels decrease internal flow velocity drops, yielding a 4% to 7% COP improvement over older HG generations.
2. Reversible Forced-Feed Oil Pump: Operates independently of motor rotational direction, ensuring positive lubrication to main sleeve bearings, connecting rod journals, and wrist pins during forward and reverse shaft spin.
3. Reinforced Heavy-Duty “S” Motor: Fitted with high-breakdown torque windings, allowing continuous duty at high condensing stages up to +55°C without nuisance thermal overloads.
4. Universal Multi-Refrigerant Certification: Compatible with conventional HFCs (R404A, R134a, R407C) and lower-GWP alternatives (R448A, R449A, R513A) using standard BOCKlub E55 POE oil.
5. Dual-Step Capacity Regulation Preparation: Cylinder covers are designed to accept optional 33% / 66% mechanical capacity control valves (unloaders) to balance fluctuating load conditions.

Applications

• Marine Provision & Cargo Refrigeration: Deep-freeze cargo holds, galley provision cold rooms, and blast freezers on container vessels, tankers, and LNG carriers.
• Shipboard Air Conditioning & Liquid Chillers: Marine air-handling package units, centralized water chillers, and offshore accommodation platforms.
• Industrial Cold Storage & Logistics: Medium- and low-temperature cold rooms, dock dispatch cooling, and supermarket pack systems.
• Process Fluid Cooling: Food and beverage processing chillers, industrial batch cooling loops, and pharmaceutical environmental chambers.

Compatible Host Systems & Skids

• Marine Air Handling & Chiller Units: Sabroe, Novenco, Dometic Marine, Carrier Transicold, York Marine, and Daikin Marine package units.
• Industrial Condensing Units: BOCK HGX series multicompressor packs, Bitzer Ecoline skid-swaps (matching footprints with adapter kits), and Copeland semi-hermetic retrofits.

Cross-Reference Part Numbers

• Bock / GEA Article Codes: HGX56e/1155-4 S, HG56e/1155-4 S (Mineral oil version), 097G4763, 097C2726, 14943
• Interchangeable Frame Replacements: Direct replacement for legacy HG6/1240-4 S, HG6/1080-4 S, and previous generation HGX5/830-4 frames (requires verifying suction manifold piping sizes).

Frequently Asked Questions

What does the “e” and “S” stand for in the BOCK HGX56e/1155-4 S model designation?

The “e” designates BOCK’s high-efficiency optimized design, featuring improved gas passage geometry and low-friction valve reed assemblies. The “S” indicates that the compressor is equipped with a reinforced, higher-power electric motor tailored for elevated condensing conditions (air-cooled systems, tropical sea-water temperatures, and wide-envelope refrigeration).

What is the displacement difference between 50 Hz and 60 Hz operation?

At a 50 Hz line frequency (1450 RPM motor speed), the displacement is 100.40 m³/h. When operating on a 60 Hz marine electrical bus (1740 RPM motor speed), the displacement increases by 20% to 120.50 m³/h.

Can I run the HGX56e/1155-4 S with modern A2L or low-GWP refrigerants?

Yes. The HGX56e/1155-4 S is fully certified for use with low-GWP HFO blend refrigerants such as R448A, R449A, R452A, and R513A. It comes standard with BOCKlub E55 synthetic POE oil, which is required for these refrigerant groups. If using mildly flammable A2L refrigerants (e.g., R454A/C), verify that your unit is configured with the ATEX/hazardous-location terminal enclosure.

What are the starting requirements for this compressor?

The unit comes configured for Part Winding Start (PWS, 50%/50% split) to lower line voltage drop during startup. It can also be wired for Direct-on-Line (DOL) operation with terminal bridging jumpers, or modulated smoothly using an external variable frequency drive (VFD) within the allowed 25 Hz to 60 Hz operating frequency range.

Which oil should be used for topping up or refilling the crankcase?

Use BOCKlub E55 synthetic polyolester oil for all HFC and HFO installations. Acceptable approved marine alternatives with identical ISO VG 55 viscosity include Fuchs Reniso Triton SE 55, Mobil EAL Arctic 46/68 (depending on application temp), and Bitzer BSE 55. Do not mix mineral refrigeration oils with synthetic POE.